How big a fan are you?

Sorry I've been gone, but ize be back! Im starting a new thing to test your knowledge of the HALO UNIVERSE. I'll ask a question, and the one to answer it becomes FAN OF THE WEEK! Please don't look these up and such, I'm counting on you not to cheat😉. you can not be fan of the week twice unless you're the only one who got it right. The FAN OF THE WEEK will be announced each Sunday.

Q: what's the Arbiter's real name?